Being aluminum, yes it will stain if you cook tomato products in it. But, you can minamize both by not storing food in it.
FWIW - I watched Justin WIlson cook gumbos and other Cajun and Creole dishes with tomatoes in Magnalite for years ...
Unfortunately, I've not only noticed that my Magnalite has pitted (interior) but it has also darkened (both surfaces)--probably, through misuse per cleaning.
These things may just be a sign of old age (and I have plenty of that, too ).
While clearing a few things from my parents house I found the above old Dutch oven w/ lid in really good condition. And, what you have is a roaster - not a dutch oven.
Can I cook tomato products in this pan w/o staining and off flavors? If I remember right - Magnalite cookware is cast aluminum (same process as making cast iron, just made from aluminum).
Cast iron was affordable, cooked really well, and is virtually indestructible if treated with common sense care.Got this 10 inch skillet at an antique store in Leavenworth, KS about 5 years ago.It was pretty rusty when I got it, but it has cleaned up nicely, although I'm still working on it.After running this site for several years, many similar questions arise, useful links and general information have been posted on the FORUM.I thought I'd try to maintain this FAQ page and compile some of these "repetitive", useful and important posts on this page as an archive.